1. Field of the Invention
The present invention relates to a storage apparatus employed in a computer system. More particularly, the present invention is concerned with a storage apparatus using a nonvolatile semiconductor memory such as a flash memory.
2. Description of the Related Art
Generally, storage apparatuses include a randomly accessible nonvolatile storage medium. The randomly accessible nonvolatile storage medium is for example, a magnetic disk (which may be called a hard disk), an optical disk, or the like. As described in, for example, a patent document 1, numerous hard disks are integrated.
In recent years, a storage apparatus using as a storage medium a nonvolatile semiconductor memory such as a flash memory in place of the conventionally employed hard disk has attracted attention. The flash memory has the merits that it can operate at a higher speed than the hard disk can and that the power consumption is limited. A patent document 2 has disclosed a technology for substituting a flash memory disk, which includes multiple flash memories and can be accessed by an accessing means for the conventional hard disk such as an accessing means conformable to the small computer system interface (SCSI) standard, for the hard disk of a storage apparatus.
Incidentally, the patent document 1 refers to JP-A-2004-5370 and the patent document 2 refers to U.S. Pat. No. 6,529,416.